Information storage devices are used to retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive is an example of an information storage device that includes one or more magnetic heads that can both read and write, but other information storage devices also include heads—sometimes including heads that cannot write. A magnetic tape drive is another example of an information storage device that uses read/write heads.
In a magnetic hard disk drive, the head typically comprises a body called a “slider” that carries a magnetic transducer on its trailing end. The magnetic transducer typically comprises a writer and a read element. The magnetic transducer's writer may be of a longitudinal or perpendicular design, and the read element of the magnetic transducer may be inductive or magnetoresistive. In a magnetic hard disk drive, the transducer is typically supported in very close proximity to a spinning magnetic disk by a hydrodynamic air bearing. To protect the transducer, it is typically coated with an overcoat material. As a motor rotates the magnetic disk, the hydrodynamic air bearing is formed between an air bearing surface of the slider of the head and a surface of the magnetic disk. The thickness of the air bearing at the location of the transducer is commonly referred to as the “mechanical flying height.”
The magnetic disk typically includes several layers near its surface, including a hard magnetic layer in which information is recorded and stored. A disk protective layer typically covers the hard magnetic layer to improve wear and corrosion resistance. The hard magnetic layer is typically supported by one or more underlayers with desired surface and/or properties. For example, in perpendicular recording applications, a magnetically soft underlayer may help channel magnetic flux beneath the hard magnetic layer.
The magnetic transducer of the head and the hard magnetic layer of the disk are typically separated by the air bearing, the transducer overcoat material, and the disk protective layer. This separation is typically referred to as the “magnetic head-disk spacing,” the “magnetic spacing,” or the “magnetic flying height.” In magnetic tape drives, the separation may be referred to as the “magnetic head-tape spacing.”
Diamond-like carbon (DLC) conventionally has been used in both the transducer overcoat and disk protective layers, because it has high density and high hardness. DLC has been shown to provide good resistance against tribological wear at the head disk interface, and good protection against corrosion of the transducer reader and of the hard magnetic layer of a disk. However, the inventors named herein have experimentally learned that DLC may not be the best overcoat material for the transducer writer in an information storage device that utilizes so-called “heat assisted magnetic recording” (HAMR). Accordingly, what is needed in the art is an improved head transducer overcoat for use on magnetic recording heads in HAMR applications.